Conventional wavefront sensors for human eye wavefront characterization are generally designed to take a snap shot or several snap shots of a patient's eye wavefront with room lighting turned down or off. These wavefront sensors generally use a CCD or CMOS image sensor to capture the wavefront data and need to use relatively complicated data processing algorithms to figure out the wavefront aberrations. Due to the fact that a CCD or CMOS image sensor generally has a limited number of gray scales and cannot be operated at a frame rate well above the 1/f noise range, these wavefront sensors therefore cannot take full advantage of lock-in detection scheme to provide higher signal to noise ratio. They cannot employ a simple algorithm to quickly derive the wavefront aberration. As a result, when these wavefront sensors are integrated with an ophthalmic device such as a surgical microscope, they generally cannot provide accurate/repeatable real time wavefront aberration measurement, especially with the microscope's illumination light turned on.
There is a need in the art for an apparatus and a method to not only realize real time wavefront measurement and display, but also address the various issues including what has been mentioned above.